Wii U Forum

Hi everyone
I just bought the Nyko U Boost for my Wii U gamepad but I am sort of confused as to how to use it. I just installed it on the gamepad which was easy, but when I put the gamepad on my charging cradle(I have the premium Wii U bundle) the U boost light is RED..so I am not sure if that means I have to charge it til the light becomes green or what it means..the Wii U gamepad itself light is no longer on so its fully charged just not sure about the U boost..so if anyone owns this and can let me know exactly how to use it would really appreciate it.